Allergic rhinitis (AR) is a common problem affecting approximately 20% of the population. AR patients suffer from many symptoms including nasal congestion, rhinorrhea, and pruritus. The impact on the quality and quantity of sleep in these patients is often an under-recognized component of the morbidity associated with AR. Nasal congestion has been primarily implicated as the cause of sleep-disordered breathing and obstructive sleep apnea, as well as fragmented sleep in these patients. Immune mediators play a role as well. Treatment of AR improves the quality of sleep and overall quality of life in these patients. AR treatment may also improve compliance with continuous positive airway pressure (CPAP) for patients who also suffer from obstructive sleep apnea.